Connector

ABSTRACT

A connector for connecting with an external terminal on an electronic component includes a spiral contact which is wound a plurality of turns. The spiral contact has a single projection that projects outwardly toward an outer circumference of the turns. When the spiral contact is in contact with the external terminal, the projection of the spiral contact comes into contact with the external terminal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.10/889,767 filed on Jul. 12, 2004, in the name of Shin Yoshida, andentitled “CONNECTOR,” which is incorporated herein by reference in itsentirety and for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connector included in a testingsocket having, for example, an electronic component such as asemiconductor. More specifically, the invention relates to a connectorthat provides a stable electrical connection between a connectionterminal on the electronic component and a connection terminal on thetesting socket.

2. Description of the Related Art

The semiconductor testing apparatus disclosed in Japanese UnexaminedPatent Application Publication No. 2002-175859 provides an interimelectrical connection between a semiconductor and an external circuitboard. A grid or matrix consisting of a plurality of spherical contactsis disposed on the back side of the semiconductor. A plurality ofdepressions is formed on an insulating substrate opposing the back sideof the semiconductor. In these depressions, spiral contacts are disposedsuch that they oppose the spherical contacts.

When the back side of the semiconductor is pressed towards theinsulating substrate, the spiral contact wraps around and comes incontact with the outer surface of the spherical contact. In this way,the spherical contacts and the spiral contacts are reliably connectedelectrically.

SUMMARY OF THE INVENTION

For the above-mentioned semiconductor testing apparatus, thecharacteristics of the semiconductor have to be measured with highaccuracy. In order to do so, spiral contacts on the semiconductortesting apparatus and the spherical contacts on the semiconductor mustbe stably connected.

There is, however, a case in which, for example, the spiral contactsundergo plastic deformation or different pressure is applied todifferent areas due to restrictions such as the shape of thesemiconductor. In such a case, the location of the electrical contactpoint between each pair of spherical contact and spiral contact differsin that, for example, a contact point is formed near the root of thespiral contact and another contact point is formed near the tip of thespiral contact. This is a problem because maintaining a stableelectrical connection between the spiral contacts and the sphericalcontacts becomes difficult.

It is often believed that a stable electrical connection can be obtainedby increasing the pressure applied to the contact points between thespiral contacts and the spherical contacts by increasing the pressureapplied to the semiconductor.

However, increasing the pressure applied to the semiconductor is notnecessarily the best solution because there is a limit to the amount ofpressure that can be applied to the semiconductor and because it ispreferable to apply less pressure to prevent damaging the semiconductor.Another reason is that the amount of pressure applied to each contactpoint decreases as the number of contact points increase and, thus,sufficient pressure may not be applied to each contact point.

An object of the present invention is to solve the above-mentionedproblems and to provide a connector that is capable of forming a stableelectrical connection between the spiral contacts on the testingapparatus and the spherical contacts on the electronic component, suchas a semiconductor, while less pressure is applied to the contactpoints. In other words, while the spring pressure of the entire spiralcontact is maintained constant, the contact area is minimized and thecontact pressure per unit area is increased so that the film on thesurface of the contact point can be easily removed.

A connector for connecting with an external terminal on an electroniccomponent includes a spiral contact which is wound a plurality of turns.The spiral contact has a single projection that projects outwardlytoward an outer circumference of the turns. When the spiral contact isin contact with the external terminal, the projection of the spiralcontact comes into contact with the external terminal.

In one example embodiment of the invention, the projection is formed ina vicinity of a tip of the spiral contact. In another example embodimentof the invention, an end of the projection constitutes an acute angle.

In the connector according to the present invention, a protrusion thatis a discontinuous contact point formed on the spiral contact on theconnector comes into contact with parts of the spherical contact on thesemiconductor. In this way, an electrical connection between the twocontacts can be maintained. In particular, since the spiral contact andthe spherical contact come into contact at the protrusion, theelectrical connection between these contacts can be stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a testing socket used for testing theoperation of an electronic component.

FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 of thetesting socket including the electronic component.

FIG. 3 is a plan view of a spiral contact according to a firstembodiment of the present invention.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3 inwhich the area between a spiral contact and a spherical contact ispartially enlarged. FIG. 4A illustrates the state before the contactscome in contact, and FIG. 4B illustrates the state after the contactscome in contact.

FIG. 5 is a plan view of a spiral contact according to a secondembodiment of the present invention.

FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5illustrating a state in which a spiral contact and a spherical contactare in contact.

FIG. 7 is a plan view of a spiral contact according to a thirdembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of a testing socket for testing theoperation of an electronic component. FIG. 2 is a cross-sectional viewtaken along line II-II of FIG. 1 and illustrates the testing socketincluding the electronic component.

As illustrated in FIG. 1, a testing socket 10 includes a base 11 and acover 12 rotatably supported at one of the edges of the base 11 by ahinge 13. The base 11 and the cover 12 are composed of a material suchas an insulating resin. On the central part of the base 11, a loadingregion 11A that is a depression towards the Z2 direction in the drawingis formed. An electronic component 1 such as a semiconductor can bedisposed in the loading region 11A. At the other edge of the base 11, alock-receiving member 14 is formed. On the cover 12, a locking member 15that engages with the lock-receiving member 14 is formed.

As illustrated in FIG. 2, the testing socket 10 is for conducting a teston the electronic component 1 including a matrix (or grid) of aplurality of spherical contacts (external terminals) 1 a disposed on thelower surface.

As illustrated in FIG. 2, the loading region 11A has a predetermineddiameter. A plurality of depressions (through-holes) 11 a penetratingfrom the front surface of the loading region 11A to the back surface ofthe base 11 is formed to correspond to each of the spherical contacts 1a of the electronic component 1. The upper surface of the depressions 11a (the front surface of the loading region 11A) includes spiral contacts(connection terminals) 20.

On the inner wall of the depressions 11 a, plated conductive regions 17are formed (refer to FIG. 4B). The upper edge of the plated conductiveregions 17 and a base 21 of the spiral contacts 20 are connected by, forexample, a conductive adhesive. The lower edge of the lower opening ofthe depressions 11 a is covered with a connection terminal 18 connectedto the conductive regions 17.

As illustrated in FIG. 2, at the lower area of the base 11, a printedboard 30 including a plurality of electrical lines and other circuitcomponents is disposed. The base 11 is fixed on the printed board 30. Onthe front surface of the printed board 30, an opposing electrode 31opposing the connection terminal 18 on the bottom surface of the base 11is disposed. When each connection terminal 18 comes into contact withthe corresponding opposing electrode 31, the electronic component 1 andthe printed board 30 are electrically connected via the testing socket10.

On the center of the inner surface of the cover 12 of the testing socket10, a pressing member 12 a projecting downwards (in the drawing) topress down the electronic component 1 is formed so that it opposes theloading region 11A. In the area opposite the hinge 13, the lockingmember 15 is formed.

A biasing member (not depicted in the drawings) including a coil springfor biasing the pressing member 12 a in a direction away from the innersurface of the cover 12 is disposed between the cover 12 and thepressing member 12 a. Thus, when the electronic component 1 is disposedin the depressions 11 a and the cover 12 is closed by engaging thelocking member 15 with the lock-receiving member 14, the electroniccomponent 1 is resiliently pressed in the direction towards the frontsurface of the loading region 11A (direction Z2).

The size of the loading region 11A of the base 11 is substantially thesame as the outline of the electronic component 1. Thus, when theelectronic component 1 is disposed in the loading region 11A and thecover 12 is locked, the spherical contacts 1 a on the electroniccomponent 1 and the corresponding spiral contacts 20 on the testingsocket 10 are accurately aligned.

First Embodiment

FIG. 3 is a plan view of spiral contacts according to a first embodimentof the present invention. FIG. 4 is a cross sectional view taken alongline IV-IV of FIG. 3 in which the area between a spiral contact and aspherical contact is partially enlarged. FIG. 4A illustrates the statebefore the contacts come in contact, and FIG. 4B illustrates the stateafter the contacts come into contact.

A spiral contact 20A illustrated in FIG. 3 is formed flush with a plane.The periphery of the spiral contact 20A is surrounded by a square base21. The base 21 is fixed to the edge of the upper opening of adepression 11 a.

As illustrated in FIG. 3, a root 22 of the spiral contact 20A is locatedat the base 21, and a tip 23 extending in a spiral from the root 22 islocated at the center of the depression 11 a.

For the spiral contact 20A according to the first embodiment illustratedin FIG. 3, the width of the root 22 is W0 and the width of the tip 23 isW1, which is slightly smaller than W0 (W0>W1). The width of the spiralcontact 20A becomes continuously smaller at a predetermined rate fromthe root 22 having a width of W0 to the tip 23 having a width of W1.

If the entire length of the spiral contact 20A, from the root 22 to thetip 23, is L and the length from the root 22 to a predetermined positioncloser to the tip 23 is X (where 0<X<L), the width of the spiral contact20A at a predetermined position X can be indicated by Formula 1 below.

$\begin{matrix}{W = {{\frac{{W\; 1} - {W\; 0}}{L} \cdot X} + {W\; 0}}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

The spiral contact 20A according to the first embodiment, however,includes a discontinuous contact region 24 having a width that differsfrom the width determined by Formula 1 and being formed at apredetermined position between the root 22 and the tip 23. In otherwords, the discontinuous contact region 24 is a protrusion protrudingfrom the side of the spiral contact 20A towards the center and which isflush with the spiral contact 20A (the discontinuous contact region 24is a protrusion on the inner circumference).

The width W of the spiral contact 20A according to the present inventionis not limited to the above and may be constant for the entire length ofthe spiral contact 20A (W0=W1). Moreover, if the resilient strength inthe Z direction can be maintained, the width of the spiral contact maybe W0<W1.

As illustrated in FIG. 4B, when the locking member 15 of the cover 12 isengaged with the lock-receiving member 14 of the base 11, the electroniccomponent 1 is pushed downwards (in the drawing) by the pressing member12 a. Therefore, each of the spherical contacts 1 a pushes each of thecorresponding spiral contacts 20A towards the inside of the depressions11 a (downwards in the drawing). Simultaneously, the outline of thespiral contact 20A is deformed so that it expands from the tip 23towards the root 22 (from the center of the spiral to the periphery ofthe spiral). In this way, the spiral contacts 20A wrap around the outersurface of the spherical contacts 1 a to electrically connect thespherical contacts 1 a and the spiral contacts 20.

Hence, the spherical contacts 1 a and the corresponding spiral contacts20 constitute connectors for electrically connecting the electroniccomponent 1 and an electrical circuit on the printed board 30. At thistime, the angular portion at the tip of the discontinuous contact region24 comes into contact with the surface of the corresponding sphericalcontact 1 a first since the discontinuous contact region 24 of thespiral contact 20A protrudes in the width direction of the spiralcontact 20A,. In other words, the spiral contact 20A and thecorresponding spherical contact 1 a can always be electrically connectedvia a contact point P on the angular portion at the tip of thediscontinuous contact region 24 and the surface of the correspondingspherical contact 1 a. Thus, the distance from the root 22 of the spiralcontact 20A and the contact point P becomes constant. In this way, achange in the electrical characteristics such as a contact resistancethat easily changes every time the spiral contact 20A and the sphericalcontact 1 a come into contact can be suppressed, and the electricalconnection between the spiral contact 20A and the spherical contact 1 acan be stabilized.

The preferable size of the contact point P for this case is 100 μm orless in diameter.

The spiral contact 20A illustrated in FIG. 3 includes a narrow region Sthat has a smaller width than the regular width of the spiral contact20A (i.e., the narrow region S has a width smaller than the width Wcalculated from Formula 1 or the predetermined constant width). A narrowregion S is formed in an area opposing the discontinuous contact region24 in respect to the central axis O and one turn outwards from thediscontinuous contact region 24.

If such a narrow region S is formed, as illustrated in FIG. 4B, when thespherical contacts 1 a come in contact with the surface of the spiralcontact 20A, the inner circumference of the narrow region S is tiltedand pressed downwards in the Z2 direction more than the outer periphery.At this time, a torsional moment M is applied to the narrow region S ofthe spiral contact 20A in a clockwise direction, as illustrated in thedrawing. Similarly, as illustrated in the drawing, a counter-clockwisetorsional moment M is applied to the area opposing the narrow region Sin respect to the central axis O. For this reason, the discontinuouscontact region 24 of the spiral contact 20A is also tilted and the innercircumference is pressed downwards.

Accordingly, as illustrated in FIG. 4B, the tip of the angular portionof the discontinuous contact region 24 easily comes into contact withthe surface of the spherical contact 1 a, and the contact point P can beformed between each spiral contact 20A and the tip of the angularportion of the corresponding spherical contact 1 a. Therefore, when thepressure applied to the contact points between the spiral contacts 20Aand the spherical contacts 1 a is small, or, in other words, when aplurality of spherical contact regions of the electronic component 1 anda plurality of spiral contacts 20A of the testing socket 10 areconnected, each of the spherical contacts 1 a and the correspondingspiral contacts 20A come into contact via each contact point P. In thisway, the electrical connection between the spherical contacts 1 a andthe corresponding spiral contacts 20A becomes stable.

Second Embodiment

FIG. 5 is a plan view of a spiral contact according to a secondembodiment of the present invention. FIG. 6 is a cross-sectional viewtaken along line VI-VI of FIG. 5 and illustrates the connection betweena spiral contact and a spherical contact.

A spiral contact 20B according to the second embodiment illustrated inFIG. 5 differs from the spiral contact 20A according to the firstembodiment in that the discontinuous contact region 24 is a protrusionprotruding towards the outer circumference of the spiral contact 20Binstead of protruding towards the inner circumference (the discontinuouscontact region 24 is a protrusion on the outer circumference).

As illustrated in FIG. 6, similar to that described above, for thespiral contact 20B according to the second embodiment, when theelectronic component 1 is pressed towards the Z2 direction, the tip ofthe angular portion of the discontinuous contact region 24 of the spiralcontact 20B comes into contact with the surface of a spherical contact 1a to form a contact point P. The spherical contact 1 a and the spiralcontact 20B are electrically connected via the contact point P. Thus,similar to the first embodiment, the electrical connection between thespiral contact 20B and the spherical contact 1 a is stabilized.

The spiral contact 20B according to the second embodiment isparticularly effective when a large torsional moment is applied to thespiral contact 20B because the diameter of the spherical contact 1 a issmall or when the pressure applied to the contact point in the Z2direction is large.

Third Embodiment

FIG. 7 is a plan view of a spiral contact according to a thirdembodiment of the present invention.

A spiral contact 20C according to the third embodiment differs from thespiral contacts 20A and 20B according to the first and the secondembodiments, respectively, in that the discontinuous contact region 24is not a protrusion and, instead, is a notch in the spiral contact 20C.Even if the discontinuous contact region 24 is a notch, thediscontinuous contact region 24 can partially come into contact with thesurface of a spherical contact 1 a and form a contact point P similar tothat described above.

Since the discontinuous contact region 24 according to the first andsecond embodiments is a protrusion and a two-dimensional structureformed on a plane, it can be formed easily by common methods such asphotolithography.

In the above embodiments, the discontinuous contact region 24 is formedon one location on the spiral contact 20. The discontinuous contactregion 24 according to the present invention, however, is not limited toone location and may be formed in a plurality of locations. When aplurality of discontinuous contact regions 24 are formed, a plurality ofcontact points P are also formed. Thus, the electrical connectionbetween the spiral contacts 20 and the spherical contacts 1 a can bestabilized even more.

In the above embodiments, the contact for the testing socket was aspherical contact (ball grid array (BGA)). The present invention,however, is not limited to this and, for example, a land grid array(LGA), ellipsoid contact, a cone contact, or a polygonal pyramid contactmay be used.

1. A connector for connecting with an external terminal on an electronic component, comprising: a spiral contact which is wound a plurality of turns, wherein the spiral contact has a single projection that projects outwardly toward an outer circumference of the turns, the spiral contact having no other projections, and when the spiral contact is in contact with the external terminal, the single projection of the spiral contact comes into contact with the external terminal.
 2. The connector of claim 1, wherein the projection is formed in a vicinity of a tip of the spiral contact.
 3. The connector of claim 1, wherein an end of the projection constitutes an acute angle.
 4. The contact of claim 1, wherein the single projection is provided on an outer edge of the spiral contact.
 5. A connector for connecting with an external terminal on an electronic component, the connector comprising: a spiral contact, including: a peripheral base portion; a single spiral arm extending inwardly from the base portion and forming a plurality of turns, the spiral arm having an inner edge, an outer edge, and a tip located substantially at a center of the turns; and a single projection projecting from the outer edge of the spiral arm outwardly toward the peripheral base portion, the spiral arm having no other projections thereon, wherein the spiral contact comes into contact with the external terminal by the single projection.
 6. The connector of claim 5, wherein the single projection is formed in a vicinity of the tip of the spiral contact.
 7. The connector of claim 5, wherein an end of the projection constitutes an acute angle. 